Documentation
¶
Overview ¶
Package aesgcm provides easy to use function to perform encryption and decryption using the secure AES-GCM AHEAD algorithm. It support AES-128, AES-192 and AES-256 key sizes. This package wraps the go's 'crypto/aes' library operations into easy to use functions like 'Encrypt' and 'Decrypt'. It also provides the required constants that are needed for dermining size of keys and nonce. Additionally it ensure a proper cryptographically secure nonce is used for the encryption process automatically when the same is not supplied.
Example ¶
package main
import (
"crypto/subtle"
"encoding/hex"
"fmt"
"github.com/boseji/auth/aesgcm"
)
func main() {
// Load your secret key from a safe place and reuse it across multiple
// Seal/Open calls. (Obviously don't use this example key for anything
// real.) If you want to convert a passphrase to a key, use a suitable
// package like bcrypt or scrypt.
// When decoded the key should be 16 bytes (AES-128) or 32 (AES-256).
key, _ := hex.DecodeString("6368616e676520746869732070617373776f726420746f206120736563726574")
plaintext := []byte("exampleplaintext")
// Encryption without Nonce, it will be automatically be generated automatically
ciphertext, nonce, err := aesgcm.Encrypt(plaintext, key, nil)
if err != nil {
panic(err.Error())
}
// Decryption should use the same nonce and key as used for Encryption
plaintext2, err := aesgcm.Decrypt(ciphertext, nonce, key)
if err != nil {
panic(err.Error())
}
// Cryptographically secure constant time comparison
if subtle.ConstantTimeCompare(plaintext, plaintext2) != 1 {
fmt.Println("Error results don't match")
return
}
fmt.Println("Success !")
}
Output: Success !
Index ¶
Examples ¶
Constants ¶
const ( // NonceSize provides the default recommended Nonce size NonceSize = 12 // KeySizeAES128 specifies the minimum Key size needed for AES-GCM-128 KeySizeAES128 = 16 // KeySizeAES192 specifies the minimum Key size needed for AES-GCM-192 KeySizeAES192 = 24 // KeySizeAES256 specifies the minimum Key size needed for AES-GCM-256 KeySizeAES256 = 32 )
Variables ¶
This section is empty.
Functions ¶
func Decrypt ¶
Decrypt function performs the AES-GCM Decryption
Example ¶
package main
import (
"encoding/hex"
"fmt"
"github.com/boseji/auth/aesgcm"
)
func main() {
// Load your secret key from a safe place and reuse it across multiple
// Seal/Open calls. (Obviously don't use this example key for anything
// real.) If you want to convert a passphrase to a key, use a suitable
// package like bcrypt or scrypt.
// When decoded the key should be 16 bytes (AES-128) or 32 (AES-256).
key, _ := hex.DecodeString("6368616e676520746869732070617373776f726420746f206120736563726574")
ciphertext, _ := hex.DecodeString("022100c774487456c404b3bb9b3938c7234b3837746a27fbd84a91df5d3ba62e")
nonce, _ := hex.DecodeString("eed01d5099dc428d44bb18f1")
// Decryption with supplied nonce and key
plaintext, err := aesgcm.Decrypt(ciphertext, nonce, key)
if err != nil {
panic(err.Error())
}
fmt.Printf("Plain Text: %s\n", plaintext)
}
Output: Plain Text: exampleplaintext
func Encrypt ¶
Encrypt function performs the AES-GCM Encryption The supplied 'plaintext' is encrypted using the 'key'. Typically a Nonce is needed for the computation involved in encryption. This can be supplied using `iNonce` parameter and should at least have a size equivalent to 'NonceSize' constant. In case no nonce is supplied then a cryptographically secure random nonce is generated (using auth.GetRandom function).
Example ¶
package main
import (
"encoding/hex"
"fmt"
"github.com/boseji/auth/aesgcm"
)
func main() {
// Load your secret key from a safe place and reuse it across multiple
// Seal/Open calls. (Obviously don't use this example key for anything
// real.) If you want to convert a passphrase to a key, use a suitable
// package like bcrypt or scrypt.
// When decoded the key should be 16 bytes (AES-128) or 32 (AES-256).
key, _ := hex.DecodeString("6368616e676520746869732070617373776f726420746f206120736563726574")
plaintext := []byte("exampleplaintext")
// Should not use a Zero Nonce for normal operation
iNonce := make([]byte, aesgcm.NonceSize)
// Encryption using a fixed or pre-set nonce
ciphertext, nonce, err := aesgcm.Encrypt(plaintext, key, iNonce)
if err != nil {
panic(err.Error())
}
fmt.Printf("Nonce: %x\n", nonce)
fmt.Printf("Cipher Text: %x\n", ciphertext)
}
Output: Nonce: 000000000000000000000000 Cipher Text: b9e3743b8019206437b8ddc1ceb150096aa14c85d9f623096ffffaf48232c4f8
Types ¶
This section is empty.
Source Files